From mboxrd@z Thu Jan 1 00:00:00 1970 From: Farkas Levente Subject: Re: Benchmarking on CentOS 5 Date: Thu, 29 May 2008 12:13:01 +0200 Message-ID: <483E81AD.9050209@bppiac.hu> References: <483D9AE5.6040509@cs.ualberta.ca> <20080528183352.GE8086@duo.random> <483DC01C.5090603@bppiac.hu> <20080529092309.GH8086@duo.random> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Cam Macdonell , kvm@vger.kernel.org To: Andrea Arcangeli Return-path: Received: from portal.bppiac.hu ([213.253.216.130]:41489 "EHLO portal.bppiac.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750952AbYE2KND (ORCPT ); Thu, 29 May 2008 06:13:03 -0400 In-Reply-To: <20080529092309.GH8086@duo.random> Sender: kvm-owner@vger.kernel.org List-ID: Andrea Arcangeli wrote: > On Wed, May 28, 2008 at 10:27:08PM +0200, Farkas Levente wrote: >> ok. so what is qumranet recommendation? > > I'm not aware of a Qumranet reccomandation for this but I can give you > my opinion. > >> the just released latest rhel 5.2 kernel is kernel-2.6.18-92.el5 is it good >> enough for kvm host os? or its' better to change some other distro eg: >> fedora 9? >> until now we try to use the latest rhel/centos on all of our servers while >> we use fedora (currently 8 but may be upgrade in a few weeks if 9 become >> stable) on desktops. but now it seems probably then for a kvm host >> rhel/centos is not enough:-( > > This is a almost the opposite question of the previous one from Cam > ;), here you're asking about a production kernel, Cam was asking for a > benchmarking setup. > > I think any distro enterprise kernel is better for production systems > than a latest mainline, but that's just me. You'll find others > preferring to run 2.6.25 in production a few days after it is > released. > > The slowdown we're talking about here for the preempt notifiers isn't > going to make a big difference in a production system, more important > that you're sure your host kernel is rock solid and well tested > IMHO. But if it was pure benchmarking what you were doing, then using > latest mainline was better to get the best possible score, that is why > such printk is there. i want rock solid, but smp guest and both 32 and 64bit guest centos too. 5-10% performance lost is not important but 50-200% is important. so my real question is that kernel-2.6.18-92.el5 has "enough" features for an good working kvm if i recompile kvm and kvm-kmod? ehough here means no more than 5-10% performance lost. -- Levente "Si vis pacem para bellum!"